There is a plasma processing apparatus using excitation of a processing gas by a high frequency wave. Such a plasma processing apparatus includes, for example, an antenna that radiates a microwave, which is an example of the high frequency wave. And, in the plasma processing apparatus, the microwave is radiated from the antenna into the processing container, and the processing gas in the processing container is ionized to ignite plasma, so that a workpiece such as, for example, a substrate is subjected to a plasma processing by the plasma.
In the plasma processing apparatus, however, when changing processes, the reflection of a high frequency wave (e.g., a microwave) may occur depending on employed processing conditions. For example, when an ignition process of igniting the plasma of the processing gas is changed to a processing process of performing a plasma processing on a workpiece, the reflection of the high frequency wave occurs. The reflection of the high frequency wave becomes a factor that damages components disposed on the upstream side of the components that supplies a high frequency wave (e.g., an antenna), and thus, is not desirable.
For such a problem, various studies have been made on a technique for suppressing the reflection of the high frequency wave by performing, between the ignition process and the processing process, an intermediate process under a different processing condition from those of the ignition process and the processing process. For example, there is a technique of performing an intermediate process using, as a processing condition, a pressure between a pressure applied to the intermediate process and a pressure applied to the processing process. See, for example, Japanese Patent Laid-Open Publication No. 2008-010598.